GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Fuel Pressure Relief

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See Figure 1

Prior to servicing any component of the fuel injection system, the fuel pressure must relieved. If fuel pressure is not relieved, serious injury could result.

A schrader valve is provided on this fuel system in order to conveniently test or release the fuel system pressure. A fuel pressure gauge and adapter will be necessary to connect the gauge to the fitting. The CMFI system covered here uses a valve located on the inlet pipe fitting, immediately before it enters the CMFI assembly (towards the rear of the engine).



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Fig. Fig. 1: Fuel pressure connection

  1. Disconnect the negative battery cable to assure the prevention of fuel spillage if the ignition switch is accidentally turned ON while a fitting is still disconnected.
  2.  
  3. Loosen the fuel filler cap to release the fuel tank pressure.
  4.  
  5. Make sure the release valve on the fuel gauge is closed, then connect the fuel gauge to the pressure fitting located on the inlet fuel pipe fitting.
  6.  

When connecting the gauge to the fitting, be sure to wrap a rag around the fitting to avoid spillage. After repairs, place the rag in an approved container.

  1. Install the bleed hose portion of the fuel gauge assembly into an approved container, then open the gauge release valve and bleed the fuel pressure from the system.
  2.  
  3. When the gauge is removed, be sure to open the bleed valve and drain all fuel from the gauge assembly.
  4.  

 
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